I think the apparent lack of interest is due to the fact that OtherCoin doesn't claim (or is expected to have) a net effect on the Bitcoin price. Its intention is to simply make off-chain truly private transactions possible. As a side effect, it would also make any blockchain transaction analysis useless (since coins could exchange hands offline hundreds or thousands of times without any trace in the blockchain or anywhere else on the Internet). It also removes the one to one mapping between addresses and persons - in the current system, once you've identified who owns a particular address, you can safely assume that any past or future payments sent to that address belong to that person. With OtherCoin in place, an address could effectively be "owned" by hundreds of people, just at different moments in time.